Hydraulic control full feathering propeller



SePf- 24, 1957 o. w. scoTT 2,807,327

HYDRAULIC CONTROL FULL FEATHERING PROPELLER fr0/sw O. W. SCOTT slept. 24, 1957 HYDRAULIC CONTROL FULL F'EA'IIHERING PROPELLER Filed July 16, 1954 3 Sheets-Sheet 2 Sept 24, 1957 o. w.- sco-r1 2,807,327

HYDRAULIC CONTROL FULL FEATHERING PROPELLER Filed July l, 1954 3 Sheets-Sheet 3 7 Y .SW 893m. Sm. QM. V L@ n. w m. Ww ha wai V m. N N, QQ

- HYDRAULIC CONTROL FULL FEATHERING PROPELLER Orin W. Scott, Wichita, Kans., assignor to Beech Aircraft Corporation, Wichita, Kans., a corporation of Delaware Application July 16, 1954, Serial No. 443,769

4 Claims. (Cl. Utl-160.32)

The invention disclosed in this patent application is a hydraulically operated full feathering propeller.

Objects of the inventionare to provide hydraulic mechanism of simple construction and consisting of few parts and compact and small enough to be combined with and practically wholly contained within the hub of the propeller.

Further objects of the invention are to provide such a construction in a well balanced symmetrical form, readily manufactured and installed, easily adjusted, reliable and quickly responsive in action.

A yfurther object of the invention is to provide hydraulic control mechanism of the character indicated which can be combined in a propeller hub of the flange mounted type. Y

Other desirable objects 4attained by the invention and the novel features olf construction, combination and relation of parts through which the purposes of the invention are accomplished are set forth and will appear more fully in the following speccation.

The drawings accompanying and forming part of the specication illustrate present commercial embodiments of the invention. Structure, however, may be modified and changed as regards the immediate illustration, all within the true intent and scope of the invention as hereinafter defined and claimed.

Fig. l in the drawings is a broken longitudinal sectional view taken through the center of the hub of the propeller;

Fig. 2 is a broken plan view looking down on the parts as they appear in Fig. l;

Fig. 3 is a front end elevation, the blades shown broken away. i

Fig. 4 is a broken sectional View similar to Fig. l, illustrating a modified form of the invention.

Figs. la, lb and 4a, 4b are broken sectional details of different forms of control orifices.

In the several views the body or hub of the propeller is designated 5, it being shown as carrying bearings 6 for the blades 7 and as having a drive sleeve 8 extending therethrough and provided with a mounting flange 9 at the back attachable to the tiange 10 of the engine shaft 11.

In the present invention the central drive sleeve 8 is finished interiorly as a containing cylinder for the longitudinally shiftable working cylinder 12, and the latter is shown as carrying a cross yoke 13 at the outer, forward end to which are pivoted, at 14, links 15, pivoted at 16 to the adjusting arms 17 of the blades.

The drag links 15 are shown as longitudinally adjustable at 18, Fig. 2, and the pivotal connections 16 at the inner or rearward ends of the links are shown as rigid studs, Fig. 3, extending from split rings 19 clamped on the base portions of the blades to a diametrical center at opposite sides of the rotational axis.

The outer end of working cylinder 12 is shown adjustably closed by a partition 20 longitudinally shiftable for low pitch adjustment by a screw 21 seated in yoke 13,

A 2,807,327 Patented Sept. 24, 1957 ICG This adjustable partition or cylinder head is shown sealed by an O-ring 22.

The inner end of operati-ng cylinder 12 is shown closed by an annular cylinder head 23 sealed in sliding engagement in the .containing cylinder by an outer O-ring 24 and slidingly sealed Vby an inner O-ring 25 over a longitudinally iixed tubular piston rod 26.

The latter carries at the outer end a piston 27 sealed to the interior of sliding cylinder 12 by O-rng 28.

The construction described provides a working cham-V ber 29, Fig. l, between stationary piston head 27 and movable cylinder head 20 for outward or forward movement of the cylinder and an annular working chamber 30 between fixed piston head 27 and the inner annular cylinder head 23 for creating inward cylinder movement.

Oil or other actuating iiuid is led to chamberv 29 in the first illustrated form of the invention, Figs. 1, 2 and 3, through center conduit 31 and conducting tube 32 sealed over the end of the conduit, at 33, and seated in the center of the piston head at the other end, at 34.

Actuating fluid for the cylinder retracting chamber 30 is shown supplied through an annular conduit 35 surrounding the center conduit 31 and connected by channels 36 with the annular space 37 between the center tube 32 and tubular piston rod 26, ports 38 in the latter admitting fluid to outer annular chamber 30.

By proper control of the iiuid under pressure supplied to chambers 29 and 3i), the blades may be positively shiftedy in either direction and held in adjustedy relation from low pitch to fully feathered condition. If desired these pressures may be balanced as required to maintainv constant speed. If the net force applied by the blades and oil pressure in chamber 29 are higher than net forces applied by the blades and pressure in chamber 30, the cylinder will move forward to shift the blades to higher pitch. If net forces are reversed the blades will be shifted in the low pitch direction.

Control may be automatic, as by governor, feathering pump or the like, or be semi-automatic or manual.

Necessary adjustments are readily effected. The drag links are exposed at the sides of the hub, fully accessible for adjustment of length. The low pitch adjusting screw 21 is exposed at the front of the hub for quick and easy adjustment. In making this adjustment the cylinder may first be set all the way in, with the head or partition 2l) against the stop 39 provided by the end of the tubular Y piston rod.

If desired a control orifice may be provided, as at the mounting of the piston on the tubular piston rod as indicated at 60, Fig. 1a, affording limited connection between the opposed pressure chambers, thus to maintain continuous circulation of oil to keep' the oil Warm at all times of propeller operation.

The structure is made up of but relatively few simple parts and action is direct and immediate. Practically all parts are housed within the propeller hub and the full diameter of the drive sleeve is utilized for pressure operation so the action, while sensitive, is positive and powerful. Parts are symmetrical and balanced, and the construction can be made up at reasonable cost as a complete unit and readily installed, inspected and serviced.

The compact symmetrical arrangement of parts enables the device to be made up for a flange mounted propeller, an advantage for quick assembly and servicing purposes. This flange-to-flange meeting enagement of propeller hub and engine shaft simplifies necessary hydraulic connections and .mounting of the piston rod, the latter shown in Fig. l as sealed at 39 in engagement over the end of the outer conduit 35 and as having an enlarged base flange 40 sealed at the meeting flanges of drive shaft and hub.

In the modified form of the invention illustrated in Fig.

larged base sealed in the stationary piston tube 26, at 41,

which is ported through from the back to the center, at 42, to pass oil to the forward expansion chamber 29, `and ported through from the center on an outward incline, at 43, to furnish oil to the annular expansion chamber 30.

In this particular instance the inner or center conduit 31a supplies oil for the annular chamber 30 and the outer annular conduit 35a supplies the fluid under pressure for the forward expansion chamber 29.

A bleed or oil warming vent between expansion chambers may be` provided by omitting O-ring 25 as shown in Fig.,1b.

. Other oricing means may be provided asby slight clearance or ne notches at 44 in the tit between the inner tube 32a and piston head 27, Fig. 4, Fig. 4a or, by provision of a loose fitting sliding pin or plug 45 Fig. 4b in the inner annular cylinder head 23. Either or both or any combination of such means may be utilized.

The hub with the drive sleeve 8 extending centrally therethrough 4and having the mounting flange 9 at the back, may be made up of separate parts or all formed in the single integral unit.

The adjusting arms 17 may be connected with the blades by split clamps such as shown at 19, Fig. 2, or any `other satisfactory form of connection may be employed.

Fig. 4 illustrates a method of mounting a spinner 46 by means of a central tension bolt 47 connected with a bridge piece 48 spanning the yoke and carried by rods 49 fastened to the flange 5t) on the outer end of the center sleeve 8.

Also attached to this flange, by bolts 51, is a centering flange 52 for` the spinner.

The base end of the spinner is shown anged at 53 and bolted at 54 to a mounting flange 55 having an inner hub `or collar 56 centered over the mounting ange 9.

In some instances it has been found practical to omit bridge piece 48 and extend the 1rods49 through the spinner, the latter then equipped with bushings or openings for the rods and fastening nuts applied to exposed ends of the rods at opposite sides of the center.

What is claimed is:

l. Hydraulic pitch control propeller mechanism comprising the combination `of a hub body having propeller bladesmounted for angular adjustment therein, said hub body having an axially extending rigid drive tube extending therethrough and open at the front end and finished interiorly as a xed guide cylinder, a movable power cylinder slidingly guided in said fixed guide cylinder, con nections extending from the front end of said movable power cylinder back to the blades for translating sliding movement of the power cylinder into angular adjustment of the blades, a tubular piston rod tixedly supported in the back end of the stationary guide tube and extending forwardly into said movable power cylinder, a stationary piston on the forward end of said tubular piston rod in cooperative relation with the movable cylinder slidably operating thereover, a cylinder head at the forward end of the movable power cylinder in opposition to said stationary piston and forming therewith an expansion charnber in front of the stationary piston, an annular cylinder head at the inner end of the movable power cylinder in slidingly sealed engagement with the stationary tubular piston rod and forming in cooperation with said rod and piston an expansion chamber in back of the stationary piston, a center supply tube within the tubular piston rod in communication at the front end with the expansion chamber in front of the piston and spaced from tubular rod to provide an annular supply passage, said piston rod being ported at the forward end in back of the piston to provide communication between said annular supply passage and the expansion chamber in back. of the piston and fluid pressure conduits in communication with said center supply tube and with said annular supply passage about the same for admitting and releasing actuating fluid to and from said expansion chambers in front and in back of the stationary piston.

2. The invention according to claim 1 in which said cylinder head at the forward end of the power cylinder is longitudinally adjustable therein and engageable with the forward end of the stationary piston rod to limit inward motion of the movable power cylinder' and in which externally accessible means are provided for elfecting longitudinal adjustment of said movable cylinder head in the power cylinder.

3. The invention according to claim l with oriicng means providing limited communication between the two expansion chambers for warming actuating tluid under operating conditions.

4. The invention according vto claim 3 in which said oricing means includes a leakage permitting connection between the opposing expansion chambers.

References Cited in the le of this patent UNlTED STATES PATENTS 1,510,436 Englesson Sept. 30, 1924 2,343,416 Keller Mar. 7, 1944 2,357,228 Seewer Aug. 29, 1944 2,379,302 Hoover June 26, 1945 2,405,285 Blanchard et al. Aug. 6, 1946 2,442,691 Holberton June 1, 194B 2,653,670 Odevseff Sept. 29, 1953 2,686,569 Bruce Aug. 17, 1954 FOREIGN PATENTS 343,653 Great Britain Feb. 26, 1931 

